Is bone marrow purging proving to be of value?

Although the role of hematopoietic stem-cell transplantation (HSCT) in cancer treatment is rapidly expanding, decreasing the side effects of stem-cell infusion is a major challenge. Cancer cells present in the stem-cell collection can cause relapse after autologous transplantation. In allogeneic transplantation. T lymphocytes contribute to graft-versus-host disease. Various methods of purging have been used to remove these unwanted cells, and there is some evidence that such manipulations are clinically useful. Nevertheless, the inability to detect minimal disease makes it difficult to determine whether relapse is caused by incomplete disease eradication in the patient or by the infused cells. This makes it hard to justify the clinical benefit of ex vivo purging. Researchers can focus on this issue by designing studies with minimal variation in other factors that affect the success of stem-cell transplantation.